Perception and Reality: The Science of Vision
A Talk by Dr Tiago Siebert Altavini, Ph.D.
As most primates we humans rely heavily on our visual perception to guide ourselves around the world and therefore our brains are very good in processing visual information about different shapes, colors and brightness variations. But putting together all the physical attributes is not enough to recognize something (or someone). To recognize something is to give meaning to it. The meaning of an object however is not an intrinsic physical feature of the object, but something also defined by internal representations in our brains, often based in past experience. You cannot recognize what you never saw. There are also many levels of recognition. I can show a green leaf and you will tell me “that’s a leaf” while someone else would tell me “that is a leaf from a red oak”. Thus visual perception is not just the processing of information about the physical attributes of what we see, but the combination of these physical attributes to the internal representations the already brain has. How is it that our memory and expectations influence our visual perception? That’s what we are trying to find out.
Tiago Siebert Altavini is a neuroscientist working in the Laboratory of Neurobiology in The Rockefeller University. He has been studying different aspects of the visual system since he was a biology undergrad student at the University of Brasilia. The interest in neuroscience of vision led him to a PhD at the University of Rio Grande do Norte where he worked with Dr. Kerstin Schmidt at the university’s Brain Institute. His PhD research was on the visual connections in the brain and their influence in patterns of spontaneous brain activity. Now working with Dr. Charles Gilbert he is investigating the top-down influence of feedback connections on object recognition. The aim of such research is to understand the mechanisms by which expectation influences visual perception.